It is often the case that in systems which include separate electronic modules that require accurate information from an environmental sensor, such as a temperature or humidity sensor, each module reads its own separate sensor. This is usually due to the fact that a calibrated reference voltage must be applied to the sensor in order to interrogate the sensed information. However, the reference voltages from the individual modules may have slightly different values at the sensor. These differences may be the result of many causes, including, for instance, the unique characteristics of the individual module circuitry or the voltage drop that occurs between the module and the sensor due to wiring and connectors. On the other hand, a single reference voltage applied to a common sensor may be slightly different from the reference voltage used by a module and therefore produce an erroneous sensor measurement to that module. Therefore, the use of a dedicated sensor with each module is the conventional way to obtain the most accurate sensor information.
In the manufacture of automotive vehicles, the use of separate sensors that detect the same environmental information, such as ambient air temperature, is a duplication that is costly. It would, of course, be desirable to eliminate such duplication and maintain the accuracy afforded by conventional practice.